The conventional lockable folding knife has as many forms as there are applications. Locking knives of various types have been utilized throughout the prior art in a lockable folding arrangement having different types of locking mechanisms fixated or attached to their handle. The lock back mechanism is one of the simplest and most reliable. In practice, the lock back mechanism includes a locking bar substantially parallel to the handle of the knife with one end aligned over the upper back or rear tang of the blade. The locking bar is usually fixated as a separate part to the handle with weld, or through pin. As the blade rotates to the open position, the locking bar rides along the rear tang with spring tension, until the locking bar engages a notch in the rear tang, locking the blade in the open position. To unlock, the opposing end of the locking bar is depressed pivoting the locking bar out of the notch and away from the rear tang allowing the blade to close.
The commonly available lock back knife has a blade, a pivot pin, a handle, and a locking mechanism. The locking mechanism, having in its simplest form, individual components such as a locking bar, pins, springs and a bolster between the two halves of the handle that all require assembly within the handle during the manufacturing process.
Other methods of locking a knife requiring a plurality of components are known in the art. An example of one alternative method is a locking liner as taught by inventor Ed Halligan in U.S. Pat. No. 6,101,724. The handle has an integral locking bar formed from the same metal as the handle and arranged to exert side forces on the side of the blade as it opens causing wear, and in gritty environments excessive wear. Tolerances for a liner lock design must be precise in order for it to work properly, whereas the tolerances for a lock back are not as critical. The lock back design takes more abuse, has less wear surface between the locking bar and the blade, and is easier and less expensive to manufacture making it the preferred design for a simple pocket knife. Further, the unlocking mechanism of #724 requires a side force applied from a direction perpendicular to the handle, and when the blade unlocks, the user's finger or thumb is aligned with the sharpened blade portion thereby exposing the user to a potential cut hazard.
There are many designs of lock back folding knives involving a plurality of necessary locking mechanism components, assembled in complex and compact handle configurations, but none achieve the reliable lock back function with the locking and unlocking mechanism being integral in the knife handle, constructed of a continuous piece of metal, requiring no additional components, no welds, or complex assembly.